Not related directly to this, but we also faced issue with rules in v7.0 .
Our MOLAP crashed when following type of rule is used:
[‘Account1’,’Jan’] = [‘Account2’] – [‘Account2’,’BegBalance’]
i.e. in first part of right hand side, there is no Month defined

Jedox provided us with a patch for this and then it worked fine.. May be you can raise a support ticket for your issue as well ..

Also, did u try to patch with 7.1 , it has solved many of rule relates issues.

Should do the job.
I's also recommend to use comparison operators that do not include equality check ( >, <, != ) than others (>=, <=, ==). It is faster in new engine that was built to eliminate need of markers.